Cleaning, Etching, Activation, and Deposition

Cleaning is a mandatory step in every processes of surface modifications. Basic cleaning operations are usually performed with a chemical treatment outside a vacuum chamber. But the treated sample inevitably pollute, being transported. Therefore the final cleaning has to be accomplished in the vacuum chamber. Plasma etching is an effective method of cleaning in vacuum. The main advantage of this method is the ability to process any kind of materials. Plasma etching is being used worldwide to remove organic and inorganic contamination, increase wettability, increase bond strength, and remove residues. These processes are under precisely controlled conditions, without the safety hazards and liquid wastes associated with wet cleaning and etching. Besides, plasma surface treatment processing usually activate the surface, promoting much better adhesion of deposited film.

The process of magnetron deposition can be improved considerably, the dedicated plasma source operating at matched regime being used. The anode layer accelerator (ALA) is one of prospective sources for this purpose. It can be used for plasma assisted magnetron sputtering, e.g. it is possible to use ALA to keep the magnetron target highly pure or keep constant conditions of synthesis on a sample.

The ALA based devices can be effectively used to produce composite and multilayer thin films. The lower rate of the film growth (compared to the case of magnetron deposition) enable more precise control of its thickness. This can be important for optical and multilayer coatings.

For nano-scale surface modification the oblique etching at the regimes with low currents under low pressure can be used. Depending on the used regime of the substrate treatment, various liquid crystal alignments can be obtained. The wide range of alignments types can be obtained using various combinations of processing regimes and liquid crystal types, even the same materials being used. This method is contact-free, it is easy to use templates to create cells with multidomain liquid crystal alignment.

The use of the ALA based devices offers a wide variety of advantages and can be effectively used in vacuum technologies to obtain single- and multi-layer coatings with various thicknesses and purposes as these devices are rater easily scalable. The creation of surface anisotropy is one more application of the ALA based devices, e.g. for liquid crystal alignment.